Yes, that's a serious scientific question, especially now that animals are moving into unfamiliar territories and bringing their poop along with them. After two years and over 9,000 dung beetles, I think you'll be pleasantly surprised by the answer...

Researchers from the University of Nebraska system tested fifteen different species of dung beetle native to the Great Plains to see just which exotic manures they enjoyed eating. They also, according to their paper, "analyzed the nutrient quality of each dung type", which really should be put on recruiting posters in elementary schools throughout the country to entice the next generation of scientists.

So then, just which type of dung proved to be the beetles' favorite?

We found significant differences in mean dung beetle capture among omnivore, herbivore, and carnivore dung, as well as differences in individual species preference for dung type. Omnivore dung was the most attractive with chimpanzee and human dung having the highest mean capture. Carrion also was highly attractive with a mean of 231.9 ± 20.6 beetles per trap. Preference for a specific bait type does not appear to be correlated with dung quality, mammalian diet, or origin of mammal. Results suggest niche segregation by dung type among dung beetle species.

That's right - human poop is number one! (Chimps can be number 1a, I guess.) It's thought that omnivore poop has a much stronger smell than its herbivore and carnivore counterparts, and that would explain why the dung beetles were so attracted to it. Well, that and the dung beetles clearly just have good taste. Intriguingly, the dung beetles proved way less interested in the poop of species they evolved alongside, such as bison, preferring instead exotic poop like that of zebras, donkeys, and moose. It appears, after a few million years of quite literally eating the same old crap, these dung beetles are ready to test their palates.